The invention relates to a device for calibrating pipes or profiles extruded from thermoplastics, in which the extrudate is cooled in an enclosed calibrating chamber, which may be under vacuum, by means of a liquid which is sprayed on to it by means of nozzles and is extracted by a pump from a receptacle arranged below the calibrating chamber in which the liquid collects again after spraying.
Vacuum calibrating devices of different constructions are known, these being used successfully and economically when air support calibrating devices cannot be used because of very small pipe or profile dimensions, very small wall thicknesses, very high extrusion speeds or because of the nature of certain plastics. Thus heat must be removed from the pipes or profiles calibrated down to the desired cross-section by means of different constructions of sleeves and discs, to such an extent that after leaving the calibrating device they no longer change their shape. Both conventional methods for this purpose, i.e. passing the extrudate either through a spray comprising jet sprayed water or through a container full of cooling liquid, have various advantages and disadvantages in terms of method, which have an effect on starting and output of the plant as well as on the accuracy as to size of the finished product.